[Alexander] Henderson argued that a minister should not ignore human learning and the original languages, but he also argued that such learning should be put to the practical use of teaching or instructing the listeners with simplicity. Calderwood had accused the bishops of filling their sermons with unnecessary and arrogant displays of rhetorical flourishes that did little more than flaunt their learning. Such parades of learning may have impressed a listener with the speaker’s eloquence, but, according to Henderson, they had little power to inflict wounds to heal the soul, which was one of the primary purposes of godly preaching.

By simplicity Henderson did not mean that preaching should be dull in content, but that it need not be decorated with unnecessary rhetoric or showy displays of learning that might distract the humble listener from plucking the fruit of the sermon. Simplicity for Henderson did not mean that sermons were empty of good illustrations or rhetorical devices. In fact, when teaching his listeners with simplicity, Henderson used several useful rhetorical devices such as illustrations to exhort them further, saying: “The test it is the tree, the interpretation is the fruit that grows upon the tree, the application thereof is the hand whereby the fruit is plucked aff [sic] the tree.” He believed that preachers should use sermons to persuade God’s people to respond to God’s word in active faithfulness, and sermons were God’s primary instrument for such persuasion.

L. Charles Jackson, Riots, Revolutions, and the Scottish Covenanters: The Work of Alexander Henderson, 112-113.